OMA POC, PAG 1.0 compliant Push-To-Talk (PTT) services are currently deployed in a SIP/IP core network, e.g. 3GPP IMS networks. In order to establish and maintain a PTT session between PTT clients, SIP signaling is utilized in SIP/IP core networks. PTT clients are resident on handsets or user equipment (UE), which are utilized by users to access a communications network. These UEs are tested in OMA IOP (Interoperability) Forum and GSM Certification Forum (GCF) for protocol and standards compliance. Testing is a lengthy process often requiring a year or more of time to complete. Once the UEs are certified, they are released into a market by UE manufacturers. Released UEs should work with any standard compliant PTT network. However, as lower end UEs often lack capability to update software in the field, they are necessarily restricted to a set of services and protocols that were initially installed on the UEs. Therefore, as networks are upgraded with new applications, it may be desirable for application vendors to come up with technologies that enable seamless integration of new applications and services to existing handsets, which could not otherwise be upgraded.
PTT System Overview
Push-to-talk Over Cellular (PoC) is standardized by Open Mobile Alliance (OMA). This standard is discussed in greater detail in the following technical specifications which are incorporated by reference:
“Push to talk over Cellular Requirements”, Candidate Version 1.0-29 Mar. 2005, Open Mobile Alliance™, OMA-RD-PoC-V1—0-20050329-C;
“Push to talk over Cellular Architecture”, Candidate Version 1.0-27 Jan. 2006, Open Mobile Alliance™, OMA-AD_PoC-V1—0-20060127-C;
“PoC XDM Specification”, Candidate Version 1.0-Jan. 20, 2006, Open Mobile Alliance™, OMA-TS-PoC-XDM-V1—0-20060120-C;
“PoC Control Plane”, Candidate Version 1.0-27 Jan. 2006, Open Mobile Alliance™, OMA-TS-PoC-ControlPlane-V1—0-20060127-C; and
“PoC user Plane”, Candidate Version 1.0-27 Jan. 2006, Open Mobile Alliance™, OMA-TS_PoC-userPlane-V1—0-20060127-C.
The OMA PoC Version 1 standard utilizes SIP protocol for session establishment, session modification, and session tear down. There are several different types of PTT sessions that the user can initiate. For example, there are 1-to-1 sessions, 1-to-many ad hoc sessions, pre-arranged sessions, and chat sessions. 1-to-1 and 1-to-many sessions allow a calling user to call a single called party or a set of called parties. In OMA PoC, each user may have one or more contact and group lists, which contain a list of URIs indicating the contact information of his/her buddies. Contact information is also known as a user selectable list. URIs may be configured as SIP URIs, Tel URIs (Telephone number represented in a URI form), email URIs, or HTTP URIs. When a calling user makes a 1-to-1 call or a 1-to-many ad hoc call, contact information about other users that the calling user wishes to be part of the call is specified in the body of a SIP INVITE message as SIP URI list. The list of users is represented in an XML format and is called the resource list. It may be desirable to make use of this particular method (i.e. adding new URIs to the body of SIP INVITE) to create a special URI (S-URI). Thus, an S-URI may be utilized indicate the type of application or service the user is trying to access.
In addition, a new IETF standard specified in RFC 3680 “A Session Initiation Protocol (SIP) Event Package for Registrations,” allows primary application servers, such as a PoC Server, to SUBSCRIBE to registration events in the SIP/IP Core. This functionality allows primary application servers to monitor the registration activity and be notified when S-URIs are registered with a network registrar. It may be desirable to utilize this functionality to detect when new secondary application servers are registering with their SIP URIs. Once a secondary application server registers with a S-URI, the PoC Server (in this case the primary application server) would store that information so that any UE requesting a new application can easily be directed to the new secondary application server identified by the S-URI. As such, systems and method for integrating applications on UE utilizing S-URI control messages are presented.